This article was previously published under Q239883
BUG #: 55964 (SQLBUG_70) BUG #: 55787 (SQLBUG_70)
SYBASE clients using a CT-Library based on Tabular Data Stream (TDS) 5.0 (including Open Client 10.0.4 and 11.1.1) cannot connect to Microsoft SQL Server 7.0.
These clients may encounter one of the following SYBASE CT-Library errors reported by SYBASE Isql.exe:
CT-LIBRARY error: ct_connect(): network packet layer: internal net library error: Net-Library operation terminated due to disconnect
CT-LIBRARY error: ct_connect(): protocol specific layer: internal Client Library error: There is a tds state machine error. An illegal tds token sequence was received.
The Microsoft SQL Server 7.0 errorlog reports the following error:
ods Error: 17832, Severity: 18, State: 7 ods Connection opened but invalid login packet(s) sent. Connection closed..
Microsoft has confirmed this to be a problem in SQL Server 7.0. This problem has been corrected in U.S. Service Pack 2 for Microsoft SQL Server 7.0. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
254561 INF: How to Obtain Service Pack 2 for Microsoft SQL Server 7.0 and Microsoft Data Engine (MSDE) 1.0
For more information, contact your primary support provider.
Microsoft SQL Server 6.5 and 7.0 are designed for backward compatibility to support TDS 4.2 clients, including TDS 4.2 clients from SYBASE. However, some of Microsoft's customers have traditionally been able to connect their SYBASE TDS 5.0 clients and perform basic queries against a Microsoft SQL 6.5 server. This configuration is not supported by Microsoft, although some customers have been using it.
Changes were made in SQL 7.0 to provide more TDS protocol checks that prevented these SYBASE TDS 5.0 clients from making the same connection as in SQL 6.5. Therefore, a change has been introduced in SQL 7.0 that allows SYBASE TDS 5.0 clients to connect. However, this does not mean the configuration is officially supported by Microsoft. TDS 4.2 is the only level of compatibility that is supported for SYBASE TDS based clients. TDS 5.0 is a SYBASE specification and it is not supported by Microsoft.
NOTE: Microsoft will not include these changes in future versions of Microsoft SQL Server. These changes will remain during the lifetime of the SQL 7.0 product, including service packs. Limited testing has been performed by Microsoft regarding the functionality of SYBASE TDS 5.0 clients with this change. Only basic connectivity is ensured.
Anyone requiring this functionality should seek a different solution for connecting SYBASE clients to Microsoft SQL Server such as using an ODBC driver or OLE-DB provider.